The present invention relates to fluid storage and transfer facilities and, more particularly, to systems for detecting pipeline leakage.
A typical storage facility may include a filling station, one or more storage tanks, a pump and a pipeline for conveying fluid from the tank, to a discharge or outlet point in a plant or the like. In many applications, the pipeline may include under ground and above ground portions. For safety and environmental reasons, it may be important to control leakage from a pipeline system and to prevent ground water contamination into the system.
Leakage detection systems have heretofore been proposed. These systems may rely upon visual inspection, the measurement of flow rates and the like to determine if leakage from the pipeline is occurring. In one method, as disclosed in U.S. Pat. No.4,206,402 entitled SYSTEM AND METHOD FOR DETECTING LEAKAGE IN A PIPELINE OR TANK, which issued on Jun. 3, 1980 to Ishido, a sensing coaxial cable is buried adjacent the pipeline or tank. The cable includes an outer conductor divided into a plurality of sections and a continuous inner conductor. The cable is fabricated from a material which prevents water from penetrating therethrough but which permits the penetration of a petroleum product. Leakage is detected by sensing the change in the dielectric constant of the coaxial cable when the cable is penetrated with a petroleum product. A system of this type will not detect ground water penetration into the pipeline.
In order to contain the fluid being stored and conveyed, many facilities employ containment jackets or outer containment pipes which surround the main pipeline. Available leakage detection systems require penetration of the containment jacket. This, of course, may have an adverse effect on the integrity of the containment system.
A need exists for a leak detection system which provides for fluid containment, which detects leakage from a main pipeline into a containment system, which does not require penetration of the containment system and which will also detect ground water contamination of the system.